Oxygen is a cornerstone of modern medicine. Whether managing acute emergencies, chronic respiratory illnesses, or perioperative care, oxygen therapy serves as a life-sustaining intervention to correct hypoxia and support cellular metabolism. However, its use must be precise, rational, and tailored, as inappropriate administration can cause harm—particularly in patients with chronic lung diseases.
This comprehensive article explores the key indications for oxygen therapy, categorized under the creative and memorable mnemonic “HARPIC-BAP.”
Oxygen Therapy: Why, When, and How
Before diving into specific indications, it is vital to understand why oxygen therapy is needed:
- To relieve tissue hypoxia
- To maintain adequate oxygenation (SpO₂ ≥ 94% in most cases)
- To prevent multi-organ dysfunction due to hypoxia
- To support metabolic demands during stress, sepsis, or trauma
Oxygen can be delivered through nasal cannula, face masks, non-rebreather masks, high-flow systems, and mechanical ventilation based on the severity of the condition.
Mnemonic: HARPIC-BAP – Indications for Oxygen Therapy
This imaginative and high-retention mnemonic—“HARPIC-BAP”—encapsulates nine essential clinical scenarios where oxygen therapy plays a pivotal role:
| Letter | Condition |
|---|---|
| H | High Altitude |
| A | Anaerobic Infections |
| R | Respiratory Paralysis |
| P | Pulmonary Oedema |
| I | Infections |
| C | COPD (Chronic Obstructive Pulmonary Disease) |
| B | Bronchial Asthma (Acute Attack) |
| A | ARDS (Acute Respiratory Distress Syndrome) |
| P | Pulmonary Hypertension |
Let’s now dive deep into each of these indications.
H – High Altitude: Combatting Hypobaric Hypoxia
At elevations above 2,500 meters (8,200 feet), the partial pressure of oxygen drops significantly, leading to hypobaric hypoxia. This may result in:
- Acute Mountain Sickness (AMS)
- High Altitude Pulmonary Edema (HAPE)
- High Altitude Cerebral Edema (HACE)
Symptoms include breathlessness, fatigue, confusion, and even coma.
Oxygen therapy is life-saving in such cases, helping to:
- Replenish alveolar oxygen
- Prevent progression to HAPE or HACE
- Allow acclimatization in climbers and high-altitude workers
A – Anaerobic Infections: Eliminating Oxygen-Sensitive Pathogens
Anaerobic organisms, like Clostridium perfringens and Bacteroides fragilis, thrive in oxygen-deprived environments. Hyperbaric oxygen therapy (HBOT) is employed especially in:
- Gas gangrene
- Necrotizing fasciitis
- Refractory osteomyelitis
Mechanism of oxygen therapy here:
- Enhances oxidative killing by leukocytes
- Inhibits anaerobic bacterial growth
- Promotes wound healing and tissue perfusion
HBOT is often adjunctive to surgical debridement and antibiotics.
R – Respiratory Paralysis: Neuromuscular Emergencies
Respiratory paralysis can result from central or peripheral nervous system compromise, including:
- Guillain-Barré syndrome
- Myasthenia Gravis crisis
- Cervical spinal cord injuries
- Botulism or organophosphate poisoning
In these patients, the diaphragm and accessory muscles become ineffective, causing hypoventilation and CO₂ retention.
Oxygen therapy, along with ventilatory support (e.g., BiPAP or invasive ventilation), is vital to maintain adequate gas exchange until muscle strength returns or the underlying cause is reversed.
P – Pulmonary Oedema: Drowning From Within
Cardiogenic pulmonary edema is most commonly caused by:
- Left ventricular failure
- Valvular heart diseases (e.g., mitral stenosis)
- Hypertensive emergencies
Fluid floods the alveolar spaces, impeding gas exchange.
Oxygen therapy serves to:
- Increase alveolar oxygen tension
- Improve arterial oxygenation (PaO₂)
- Reduce work of breathing
In severe cases, CPAP or PEEP (positive end-expiratory pressure) is added to push fluid out of the alveoli and recruit lung units.
I – Infections: Hypoxia in Sepsis and Pneumonia
Severe infections, especially community-acquired pneumonia, COVID-19, and sepsis, often present with hypoxemia. Causes include:
- Alveolar filling
- Capillary leak syndrome
- ARDS development in severe sepsis
Here, oxygen therapy:
- Corrects hypoxia
- Reduces pulmonary vasoconstriction
- Prevents progression to multi-organ failure
Oxygen delivery devices are chosen based on severity—from nasal cannula to high-flow nasal oxygen (HFNO) and even mechanical ventilation.
C – COPD: A Double-Edged Sword
Chronic Obstructive Pulmonary Disease is a common yet nuanced indication for oxygen therapy. In exacerbations, patients may present with:
- Hypoxia
- CO₂ retention
- Respiratory acidosis
Controlled oxygen therapy is essential. Overzealous administration may suppress the hypoxic drive in CO₂ retainers, leading to worsened hypercapnia.
Target SpO₂: 88–92% in most stable COPD patients. Delivery is usually via Venturi masks for precise FiO₂ control.
B – Bronchial Asthma (Acute Attack): Hyperreactive Airways
Acute asthma exacerbation is characterized by:
- Bronchospasm
- Mucosal edema
- Airway inflammation and obstruction
Patients experience hypoxia due to V/Q mismatch and dynamic hyperinflation.
Oxygen therapy helps by:
- Improving oxygen delivery to tissues
- Reducing hypoxic pulmonary vasoconstriction
- Supporting organ function while bronchodilators take effect
Delivery route: High-flow face mask or nasal cannula, depending on severity.
A – ARDS (Acute Respiratory Distress Syndrome): The Severe Form
ARDS is an inflammatory lung injury marked by:
- Diffuse alveolar damage
- Non-cardiogenic pulmonary edema
- Severe hypoxemia (PaO₂/FiO₂ < 200)
Common causes: Sepsis, trauma, aspiration, pancreatitis, COVID-19.
Oxygen therapy, often with PEEP, high FiO₂, and lung-protective ventilation, is the foundation of supportive care.
In refractory hypoxemia, prone positioning and extracorporeal membrane oxygenation (ECMO) may be considered.
P – Pulmonary Hypertension: Oxygen as a Vasodilator
In pulmonary hypertension (PH), elevated pulmonary artery pressures lead to:
- Right heart strain/failure
- Dyspnea
- Hypoxemia (especially on exertion)
Oxygen therapy in PH:
- Acts as a pulmonary vasodilator
- Reduces pulmonary vascular resistance
- Improves exercise tolerance and quality of life
It is especially indicated in Group 3 PH (due to lung diseases and hypoxia).
Case Study Highlights: Real-World Application of HARPIC-BAP
| Case | Patient Profile | Diagnosis | Role of Oxygen |
|---|---|---|---|
| 1 | 35-year-old trekker with dyspnea at 3,000m | High altitude illness | Oxygen prevented AMS progression |
| 2 | 70-year-old diabetic with foot infection | Clostridial myonecrosis | HBOT + surgery saved limb |
| 3 | Young man with ascending paralysis | GBS | Oxygen + NIV avoided intubation |
| 4 | Elderly hypertensive with frothy sputum | Cardiogenic pulmonary edema | CPAP + oxygen stabilized vitals |
| 5 | Smoker with 30-year history and acute dyspnea | COPD exacerbation | Controlled oxygen therapy normalized pH |
| 6 | Teen with history of asthma presenting with wheeze | Acute asthma attack | Oxygen + nebulized bronchodilators resolved symptoms |
| 7 | Middle-aged woman with COVID-19 pneumonia | ARDS | HFNO followed by ventilation maintained SpO₂ |
| 8 | 40-year-old male with ILD and elevated PAP | PH | Long-term oxygen reduced right heart strain |
General Guidelines for Oxygen Administration
| Setting | Target SpO₂ | Delivery Device | Notes |
|---|---|---|---|
| General | 94–98% | Nasal cannula, face mask | Titrate as per need |
| COPD | 88–92% | Venturi mask | Avoid suppressing hypoxic drive |
| High flow demand | >90% | NRBM, HFNC | In critical illness |
| Mechanical ventilation | Individualized | Ventilator circuit | For intubated patients |
Precautions & Oxygen Toxicity
While oxygen is lifesaving, overuse or prolonged administration can lead to:
- Oxygen toxicity (especially at FiO₂ > 60%)
- Absorptive atelectasis
- CO₂ retention in COPD
- Drying of mucosa
- Fire hazard in enclosed environments
Principle: Use the lowest FiO₂ that achieves adequate oxygenation.
Summary Table: “HARPIC-BAP” Mnemonic for Indications of Oxygen Therapy
| Mnemonic | Clinical Indication | Oxygen's Role |
|---|---|---|
| H | High Altitude | Counteracts hypobaric hypoxia |
| A | Anaerobic Infections | Enhances immune function, suppresses pathogens |
| R | Respiratory Paralysis | Supports ventilation and oxygenation |
| P | Pulmonary Edema | Improves PaO₂, reduces work of breathing |
| I | Infections | Reverses sepsis-induced hypoxia |
| C | COPD | Maintains oxygenation without CO₂ retention |
| B | Bronchial Asthma | Relieves hypoxia during acute attacks |
| A | ARDS | Improves oxygenation in severe lung injury |
| P | Pulmonary Hypertension | Reduces pulmonary vascular resistance |
Frequently Asked Questions (FAQ)
Q1: Is oxygen therapy always required in breathlessness?
No. Not all breathlessness is due to hypoxia. Clinical judgment and pulse oximetry (SpO₂) should guide therapy.
Q2: What SpO₂ should I target in COPD patients?
Usually 88–92%. Higher values may worsen hypercapnia.
Q3: Is oxygen therapy harmful?
When misused, yes. Oxygen toxicity, CO₂ retention, and fire risks are concerns.
Q4: What is hyperbaric oxygen therapy used for?
Gas gangrene, decompression sickness, carbon monoxide poisoning, and refractory wounds.
Q5: Can oxygen be administered at home?
Yes. Long-term oxygen therapy (LTOT) is prescribed for chronic hypoxemia in COPD, ILD, and PH.
